Memory Cards, HDDs, and Network Adapters are all regionless. The only difference on any is that the US one has a 56k modem, and the rest don't.
Originally Posted by dapoopta
You have to install the exploit using a system from the same region you intend to use it on. Each region has its own Your System Configuration file, and the exploit will only install to the file for the regions the system running it is from, hence why you can't install the exploit on a US system and then use it on a Japanese one. You need to install it on a PAL system to use it on a PAL system. After that, just copy the file to other Memory Cards as needed, if any of your friends with PAL systems want to use it.
My PlayStation2 HDD guide.
NTSC J SCPH 30000 with HDD and PSBBN 0.32
NTSC U/C SCPH 30001R Astral Blue LE PS2
Final Fantasy XI status:
Server - Ragnarok, Race - Mithra, Jobs - BLM 72 WHM 51 SCH 39 SMN 25, Nationality - Windurst, Name - Bungiefan